Every Wikipedia
on HN’s Top 5

A pencil game simpler than dots and boxes, and much less tame

Sprouts (game)

Posted as “Sprouts game”

Sprouts is an impartial paper-and-pencil game that can be analyzed for its mathematical properties. John Horton Conway and Michael S. Paterson invented it at Cambridge University in the early 1960s. The setup is simpler than dots and boxes; the play, the article says, develops much more artistically and organically.

The setup is even simpler than the popular dots and boxes game, but gameplay develops much more artistically and organically.

Conway is one of the people this crowd treats as an ancestor, and Sprouts is his most portable trick: rules you can teach in fifteen seconds attached to an analysis that refuses to stay small. The appeal is the gap between the two, a game whose entire state fits on a napkin and whose theory does not. Sixty-four points was enough to lead the day in 2008, when the site was small enough that a pencil game could outscore Stanford teaching helicopters to fly themselves.

DetailConway and Michael S. Paterson invented it at Cambridge University in the early 1960s.

64 points by Rexxar 1 September 2008 16 comments

Hacker News found it again on 1 Apr 2012.

Also on the front page that day85 stories posted

1. #2Usability Tip: Use Verbs as Labels on Buttons53
2. #3Stack Overflow: the Blind Leading the Blind47
3. #4Stanford's "autonomous" helicopters teach themselves to fly36
4. #5Update On The TechCrunch Tablet: Prototype A33
5. #6Will memristors prove irresistible?32

The fence you cannot see, that the cattle cannot cross

Ha-ha

Posted as “Ha-ha wall”

A ha-ha is a recessed barrier: a turfed incline running down to a sharply vertical face, usually a masonry retaining wall. From the garden side the view over the landscape beyond is uninterrupted; from the other side it is a wall grazing livestock cannot get past. One of its French names is saut de loup, literally wolf jump, and the name ha-ha comes from the surprise of coming upon the thing.

The name comes from viewers' surprise when seeing the construction.

A boundary that enforces itself while staying out of the interface is a pattern this crowd already believes in, and here it is executed in turf and stone by people who had no vocabulary for it. The whole mechanism is legible in a single cross-section, which is the highest compliment available on Hacker News. The article then notes that security design uses the same trick to deter vehicles without admitting to a barrier, which is the line that turns garden history into an argument about hostile architecture.

DetailIt also goes by sunk fence, blind fence, ditch and fence, deer wall and foss.

592 points by EndXA 24 August 2019 110 comments

Also on the front page that day505 stories posted

1. #1Software Architecture Guide803
2. #3Does the Amazon provide 20% of our oxygen?313
3. #4Using Backblaze B2 and Cloudflare Workers for free image hosting282
4. #5Rabbit Holes: The Secret to Technical Expertise276
5. #6Apollo Guidance Computer switching power supply works after 50 years234

Continuous spin in, one crisp step out, and no electronics anywhere

Geneva drive

The Geneva drive translates continuous rotation into intermittent rotary motion. A pin on the drive wheel reaches into a slot on the driven wheel and advances it one step at a time, and an elevated circular blocking disc on the drive wheel locks the driven wheel in position between steps.

The drive wheel also has an elevated circular blocking disc that "locks" the rotating driven wheel in position between steps.

Programmers recognise it on sight as a state machine that happens to be made of steel: discrete transitions, and an invariant held between them by geometry rather than by a lock somebody remembered to acquire. The blocking disc is the part people fixate on, because it means the thing cannot rest in an intermediate state even if you shove it. It is also completely legible, which is rarer than it should be; one animation and you own the idea permanently.

DetailOne pin, one slot, one step per pass, with a raised blocking disc holding the position in between.

481 points by Arjuna 17 December 2013 71 comments

Also on the front page that day923 stories posted

1. #1I Got Myself Arrested So I Could Look Inside the Justice System834
2. #3We Need to Talk About TED415
3. #4Show HN: Myth – CSS the way it was imagined357
4. #5CSS animated loading indicators327
5. #6We work a 4-day week and just raised $4.75m (2012)271

95% liquid water, and it comes out as a dry white powder

Dry water

Dry water, also called empty water, is a form of powdered liquid: an air and water emulsion in which the water droplets are surrounded by a coating of silica. The coating stops the droplets combining and turning back into a bulk liquid, so the material stays a white powder even though it is 95% liquid water.

Dry water consists of 95% liquid water, but the silica coating prevents the water droplets from combining and turning back into a bulk liquid.

The whole mechanism fits in one sentence: coat the droplets, they cannot coalesce, the bulk phase never forms. No new physics, no exotic ingredient, just a surface trick with a result your intuition flatly refuses to accept. That pairing, a startling object plus a mechanism you can hold entirely in your head, is close to the ideal shape of a Hacker News submission.

DetailThe powder is 95% liquid water; the silica shell is all that stops it becoming a puddle.

543 points by tacon 11 September 2018 180 comments

Also on the front page that day965 stories posted

1. #1Amazon is stuffing its search results pages with ads944
2. #2The Effectiveness of Publicly Shaming Bad Security580
3. #4Dark Motives and Elective Use of Brainteaser Interview Questions290
4. #5Deep image reconstruction from human brain activity (2017)288
5. #6Americans Want to Believe Jobs Are the Solution to Poverty. They’re Not280

The ice that grows like hair out of dead wood is a fungus at work

Hair ice

Hair ice, also called ice wool or frost beard, forms on dead wood in the shape of fine silky hair. It is somewhat uncommon, reported mostly between 45 and 55 degrees North in broadleaf forests. Alfred Wegener described it in 1918 and assumed a fungus was the catalyst; Gerhart Wagner and Christian Maetzler mostly confirmed that in 2005, and in 2015 the fungus Exidiopsis effusa was identified as key.

The meteorologist (and discoverer of continental drift) Alfred Wegener described hair ice on wet dead wood in 1918, assuming some specific fungi as the catalyst

A common substance behaving in a way that looks manufactured is the draw, with a living organism turning out to be the missing term in the equation. There is also the century-long lag the audience enjoys: a guess in 1918 that nobody could confirm until 2005 and nobody could name until 2015. Wegener showing up as the original observer, of all people, is the detail the extract itself cannot resist.

DetailIn 2015 the fungus Exidiopsis effusa was identified as key to hair ice formation.

405 points by lentil_soup 12 June 2018 69 comments

Also on the front page that day885 stories posted

1. #1Id Software516
2. #2Vue Native429
3. #4Psychedelics could heal brain cells in people suffering from depression: study367
4. #5Solar Surpasses Gas and Wind as Biggest Source of New U.S. Power362
5. #6The Trouble with D3350

Cooking salmon in the dishwasher, over the makers' warnings

Dishwasher salmon

Dishwasher salmon is prepared by wrapping the fish in aluminum foil and running it through a full dishwasher cycle. Dishwasher companies and Consumer Reports have flagged problems with the method, including inconsistent temperatures and a risk of food poisoning.

Dishwasher companies and Consumer Reports have identified potential issues, including inconsistent temperatures and the risk of food poisoning.

The pitch is an appliance already in the house being read as a hot water bath with a timer, which is one step from sous vide and one step from salmonella, and the article declines to settle which. That is a testable dispute with cheap equipment, so the thread turned into people reporting cycle temperatures and arguing about the thermal mass of foil. It drew 371 comments against 466 points, a ratio that marks an argument rather than an appreciation.

DetailThe technique is one full dishwasher cycle with the salmon wrapped in aluminum foil.

466 points by mothershipper 16 April 2023 371 comments

Also on the front page that day656 stories posted

1. #1Why does a plastic-wrapped turkey sandwich cost $15 at the NYC airport?671
2. #2Lofi air traffic control – LAX607
3. #3Google CEO: “can we change the setting of this group to history-off” [pdf]510
4. #5WebGPU Fundamentals429
5. #6The Red Hat model only worked for Red Hat322

Berlin, 1912: a key that refuses to let you leave the door open

Berlin key

The Berlin key, in German Schließzwangschlüssel and also called a forced-locking key, is a key for a type of door lock, designed to force people to close and lock their doors behind them, usually a main entrance or the gate into a shared yard. It answered a problem that dated to the 19th century: access through the communal doors of tenement blocks, or Mietskasernen. The Berlin locksmith Johannes Schweiger invented the system, and Albert Kerfin & Co mass produced it starting in 1912.

It was designed to force people to close and lock their doors, usually a main entrance door or gate leading into a common yard or tenement block.

This is policy compiled into brass: the rule is not posted on the door, it is built into the object, and the enforcement happens in the hardware. Readers here spend their working lives trying to make correct behaviour the easy path and usually settle for a warning dialog, so a lock whose stated purpose is to force people to lock it reads as an existence proof. It also invites the reflex that follows every enforcement design, which is to ask what the failure mode looks like; 147 comments went somewhere.

DetailAs of 2005, an estimated 8,000 to 10,000 Berlin keys were still in use in the city.

446 points by woozyolliew 29 September 2019 147 comments

Also on the front page that day566 stories posted

1. #1Starship Prototype Unveiled543
2. #2Text Rendering Hates You542
3. #320,000 Startup Ideas461
4. #5Which companies are using Erlang, and why?394
5. #6Ships fitted with ‘cheat devices’ to divert poisonous pollution into sea394

A 3,000-year-old way to move water without letting it evaporate

Qanat

The qanat, developed in ancient Iran roughly 3,000 years ago, carries water from an aquifer or well to the surface through an underground aqueduct. The same design runs across Asia and North Africa under regional names including kariz in Afghanistan and Pakistan, foggara in Algeria, khettara in the Atlas Mountains, and the daoudi falaj in Oman and the UAE. Beyond eliminating most evaporation, it holds up well against floods, earthquakes, and wartime destruction.

a qanat enables water to be transported over long distances by largely eliminating the risk of much of it evaporating on the journey

Gravity-fed, and it solves the loss problem by simply refusing to expose the water to air on the way: this is the profile of engineering the site calls elegant without any irony in the word. The durability argument lands harder still, since a distributed system that survives earthquakes and armies with no central operator is the thing most people here are currently failing to build. A design first cut three thousand years ago and still carrying water does not hurt the case.

DetailQanats date back roughly 3,000 years, and the largest working ones outside Iran are in Afghanistan, Xinjiang, Oman, and Pakistan.

423 points by vinnyglennon 11 November 2023 100 comments

Hacker News found it again on 18 May 2016.

Also on the front page that day663 stories posted

1. #1How I got here925
2. #2It's still easy for anyone to become you at Experian874
3. #3Your small imprecise ask is a big waste of their time501
4. #5Show HN: I spent 6 months building a C debugger as a 17-year-old393
5. #6Gnome Receives €1M from German Government375

One mould, one shot, the most common plastic chair on Earth

Monobloc (chair)

Posted as “Monobloc chair”

A lightweight stackable polypropylene chair, usually white, often described as the world's most common plastic chair. The name comes from mono- and bloc, describing an object injection moulded in one piece. Wikipedia's opening summary of it runs to two sentences, and this entry stays close to them.

The Monobloc chair is a lightweight stackable polypropylene chair, usually white in color, often described as the world's most common plastic chair.

It is the physical world's standard library: unbranded, effectively unattributed, present anywhere anyone needs seating, and the default answer to the question of what to sit on. Engineers respond to the manufacturing constraint doing all the design work, since a single mould shot and a stackable profile explain the shape, the price, and the ubiquity at once. A two-sentence summary produced 117 comments, which tells you the page was a prompt rather than a source.

DetailThe name is mono- ("one") plus bloc, meaning the entire chair is injection moulded as a single piece.

381 points by ZeljkoS 22 February 2020 117 comments

Also on the front page that day613 stories posted

1. #1Does memory leak? (1995)503
2. #2Learn Rust with entirely too many linked lists (2019)388
3. #3Inrupt, Tim Berners-Lee's Solid, and Me384
4. #5My Startup Failed, So We Open-Sourced the Tech337
5. #6M3DB, a distributed timeseries database320

The particle accelerator whose answer changed by the hour

Large Electron–Positron Collider

Posted as “Why the Z boson had a different mass at different times of day.”

LEP was one of the largest particle accelerators ever constructed, built at CERN, the multi-national centre for research in nuclear and particle physics near Geneva, Switzerland. Wikipedia's intro runs to two sentences and gives away nothing beyond the machine's scale and its address.

The submission sold a measurement problem rather than a machine: the Z boson mass came out different at different times of day. That is a shape this crowd cannot walk past, an instrument so precise that its own surroundings show up in the readings. The Wikipedia intro on file does not explain the effect at all, so the hook lives entirely in the submitter's framing. Sixty-five points put it fourth out of the 249 stories posted that day, which is what a top-five day looked like in 2009.

DetailLEP was built at CERN, near Geneva, Switzerland, and ranked among the largest particle accelerators ever constructed.

In 2009 /wiki/LEP redirected to CERN's collider; it is a disambiguation page now.

65 points by jlangenauer 8 August 2009 22 comments

Also on the front page that day249 stories posted

1. #1How Much Will the Post Office Put Up With?127
2. #2Tesla Says It Is Now Profitable, Ships 109 Roadsters In July74
3. #3What's on an airline baggage tag?68
4. #5Escherization62
5. #6Google exposes security cameras60

Detectors shielded with steel salvaged from pre-atomic shipwrecks

Low-background steel

Steel produced before the first nuclear detonations of the 1940s and 1950s is called low-background, pre-war, or pre-atomic steel, and it is typically recovered from scrapped ships, salvaged shipwrecks, and other artifacts of the period. It shields particle detectors and whole-body counting equipment, because steel made since then carries traces of nuclear fallout. Ancient lead does the same job for especially sensitive instruments.

it is often used as a shielding material for particle detectors and whole-body counting equipment because more modern steel is contaminated with traces of nuclear fallout

It is a supply-chain constraint with a hard cutoff date: past a certain point the raw material for a whole class of instrument stopped being manufacturable, and the only remaining supplier is the past. This community likes contamination that is global, invisible, and permanent, and it likes the salvage economy that grows up around it. The closing joke tells itself, which is that the fix for a nuclear-age measurement problem involves going diving.

DetailFor especially sensitive equipment, other low-background materials such as ancient lead are sometimes used instead.

359 points by confeit 19 July 2020 107 comments

Hacker News found it again on 25 Oct 2013, 19 Jun 2016.

Also on the front page that day716 stories posted

1. #1OpenAI's GPT-3 may be the biggest thing since Bitcoin1079
2. #2On Trouser Pockets769
3. #3Hugelkultur: Raised Garden Beds401
4. #4NoiseTorch: Real-time microphone noise suppression on Linux written in Go390
5. #6Swiss Political System: More Than You Ever Wanted to Know304

A wheel that keeps spinning with a rod stuck through its spokes

Shaft passer

A shaft passer lets a spoked wheel rotate even though a shaft runs between its spokes. The article concedes the device is usually raised as a joke, then points out that working examples exist. It cites Heron around 100 CE and a physical build from 2023.

The device is usually mentioned as a joke between nerds, in the manner of a fool's errand, however, examples do exist.

The setup reads as a geometry violation, which is precisely the shape of thing engineers cannot leave alone; the immediate reflex is to sketch a linkage and check whether the impossibility is real or merely unfamiliar. Better still, the article volunteers that this is a joke in the manner of a fool's errand, then undercuts itself with existence proofs about nineteen centuries apart. The horse statue is the detail that sells it: an ancient statue built so a sword passes through the neck and the head stays on.

DetailAround 100 CE Heron described a horse statue whose neck used a shaft passer, so a sword could slice through it without detaching the head.

199 points by earthrise 29 November 2013 65 comments

Also on the front page that day528 stories posted

1. #1Show HN: Probabilistically Generating HN Post Titles683
2. #2Why GNU grep is fast (2010)495
3. #3Facebook317
4. #4A universal income is not such a silly idea308
5. #6Myth: The astronauts didn’t float away because they had heavy boots169

A radiation unit you can eat, and the reason it does not add up

Banana equivalent dose

Banana equivalent dose expresses a quantity of ionizing radiation as the number of bananas you would have to eat to match it, bananas being naturally radioactive thanks to potassium-40. One BED is usually quoted at 0.1 microsieverts. Wikipedia is firm that it was never formally adopted as a dose measurement and exists purely as a teaching device.

however, in practice, this dose is not cumulative, as the potassium in foods is excreted in urine to maintain homeostasis

Sieverts mean nothing to a human nervous system and bananas mean everything, so the unit is a pure act of interface design for risk, which is catnip for people who spend their days choosing what a number should be displayed in. The better half of the appeal is the footnote that breaks it: the dose is not cumulative, because the body holds potassium at a set point and flushes the surplus. A unit that works for one banana and is wrong for a thousand is exactly the sort of leaky abstraction this crowd collects.

DetailOne banana equivalent dose is pegged at about 0.1 microsieverts, and it is not a formally adopted measurement.

470 points by soyelmango 14 June 2010 84 comments

Hacker News found it again on 2 May 2023.

Also on the front page that day413 stories posted

1. #2SeaMicro drops an atom bomb on the server industry260
2. #3Writing great documentation243
3. #4Need to process payments?183
4. #5Out of Sync: Puberty at age 9142
5. #6How to Succeed as a Consultant137

A square quartered forever, and why the shading totals one third

File:Geometric series 14 square2.svg

Posted as “A visualization of why 1/4 + 1/16 + 1/64 + 1/256 + ... = 1/3”

This is a Wikimedia Commons file page, not an article: a single diagram with a licence attached. The image is a proof without words, in which a square is repeatedly quartered and one quarter shaded at each step. The accumulated shading is the sum of the series, and it settles on exactly one third.

a square is repeatedly quartered, and shading one quarter at each step shows that 1/4 + 1/16 + 1/64 + ... converges to exactly 1/3

Hacker News has a standing appetite for arguments you can finish by looking. There is no limit notation here and nothing to take on faith; the geometry does the convergence for you, and the answer being 1/3 rather than something rounder is the part that makes people sit up. It finished as the single highest-scoring story posted that day, ahead of an iPhone development guide and a post on NoSQL, which is a fair measure of how much this crowd prefers a demonstration to an explanation.

DetailThe infinite sum 1/4 + 1/16 + 1/64 + ... lands on exactly 1/3.

200 points by Flemlord 21 July 2009 47 comments

Also on the front page that day300 stories posted

1. #2Speechless: Dilbert Creator's Struggle to Regain His Voice156
2. #3Chinese engineer commits suicide after losing a 4th generation iPhone prototype109
3. #4My Thoughts on NoSQL107
4. #5iPhone development emergency guide100
5. #6Could you Survive Without Money? Meet the Guy Who Does.85

A trend shows up group by group, then flips when you pool them

Simpson's paradox

Posted as “Simpson's paradox: why mistrust seemingly simple statistics”

Simpson's paradox is the case where a trend visible in several groups of data disappears or flips once the groups are pooled. Wikipedia notes it turns up most often in social science and medical statistics, and that it does the most damage when frequency data are handed a causal reading. The article says it resolves once confounding variables and causal relations are modelled properly.

Simpson's paradox is a phenomenon in probability and statistics in which a trend appears in several groups of data but disappears or reverses when the groups are combined.

This is the failure mode sitting under every A/B dashboard the site's readers were building in 2009: split by segment, ship the winner, watch the aggregate move the wrong way. The community treats a statistical trap the way it treats a race condition, as something that will quietly return a plausible wrong answer unless you already know its exact shape. Seventeen comments and the top slot of the day, which is roughly the ratio you get when nobody has anything to add because everyone has been bitten.

DetailEdward H. Simpson wrote it up in 1951, Karl Pearson had noticed something similar in 1899, and the name itself only arrived in 1972 from Colin R. Blyth.

Also submitted as Simpsons paradox.

152 points by waldrews 28 August 2009 17 comments

Hacker News found it again on 29 Jul 2011, 11 Mar 2024.

Also on the front page that day274 stories posted

1. #2America's unjust sex laws118
2. #3Buy somebody lunch102
3. #4A design pattern is an artifact of a missing feature in your chosen language85
4. #5Mark Bao's startup Atomplan acquired. Congratulations!64
5. #6Clamato: A Smalltalk Dialect for Javascript58

100 kg of potatoes lose half their weight to one percentage point

Potato paradox

The potato paradox asks what 100 kg of potatoes weigh after drying from 99% water to 98% water. The answer is 50 kg: the 1 kg of dry mass never changes, and doubling its share of the total from 1% to 2% can only happen by halving the total. In Quine's classification this is a veridical paradox, meaning the result is correct and merely feels wrong.

Fred brings home 100 kg of potatoes, which (being purely mathematical potatoes) consist of 99% water.

It is a three-line proof anyone can follow and almost nobody predicts, which is the exact shape that produces 132 comments. Underneath it is a lesson this crowd applies for a living and still gets caught by: percentages measured against a moving denominator do not behave like quantities, which is how capacity planning and benchmark numbers go wrong. And the article knows exactly what it is doing when it specifies purely mathematical potatoes.

DetailA single kilogram of unchanging dry mass is the whole reason the answer is 50 kg.

559 points by Panoramix 15 July 2015 132 comments

Hacker News found it again on 12 Aug 2018.

Also on the front page that day816 stories posted

1. #1The Icy Mountains of Pluto591
2. #31.5 TB of Dark Net Market scrapes364
3. #4Thanks Pivotal, Hello Redis Labs347
4. #5Keybase raises $10.8M343
5. #6Vim's 400 line function to wait for keyboard input296

A list that never prints the false thing, only the correction

List of common misconceptions

A standing catalogue of widely accepted viewpoints and factoids that are actually false. The list follows a structural rule: every entry is phrased as a correction, so the misconception itself is implied rather than stated. Wikipedia traces the sources to conventional wisdom, stereotypes, superstitions, logical fallacies, misunderstandings of science, and popularized pseudoscience and pseudohistory.

Each entry on these lists of common misconceptions is phrased as a correction; the misconceptions themselves are implied rather than explicitly stated.

This is the raw material of half the comment threads on the site, industrialized into a single page. The format also works on the reader in a specific way: because the false claim is never printed, you have to catch yourself believing it as the correction goes past. And every line is an implicit invitation to argue about sourcing, which is the native activity here.

DetailThe page never states a misconception outright; each entry is written only as its correction.

Also submitted as Common misconceptions.

169 points by huhtenberg 27 June 2010 53 comments

Hacker News found it again on 14 Jun 2018, 22 May 2020.

Also on the front page that day204 stories posted

1. #1Microsoft by the Numbers170
2. #3I don't like Python. Does that make me a bad person?151
3. #4Always ship trunk: Managing change in complex websites 138
4. #5Scientist who cured type I Diabetes in mice was denied funding for human trials134
5. #6No more confusions on tricky C declarations132

You believe the glass floor holds. Something in you disagrees

Alief (belief)

Posted as “Alief”

An alief is an automatic or habitual belief-like attitude, particularly one in tension with what a person explicitly believes. The article's examples are bodily rather than abstract: the transparent balcony you know is safe, the sad film you know is fictional, the fudge moulded into the shape of feces.

For example, a person standing on a transparent balcony may believe that they are safe, but alieve that they are in danger.

The word names a bug report many engineers have quietly filed against themselves. The model says safe, the hardware says no, and both keep running, which is a two-process account of a mind without any of the usual pop-psychology scaffolding. Every example is testable on yourself in about a second, and handing this crowd a precise term for something they had noticed but could not name is enough to put a philosophy page in the day's top three.

DetailThe article's examples include hesitating to eat fudge formed into the shape of feces, and reluctance to drink from a sterilized bedpan.

307 points by jkuria 7 July 2013 52 comments

Also on the front page that day352 stories posted

1. #1Asiana Airlines Boeing 777 crashes at SFO358
2. #2In Secret, Court Vastly Broadens Powers of N.S.A.329
3. #4Google Correlate - Draw223
4. #5An easy way to share files P2P, and how it works175
5. #6Python: Common Newbie Mistakes, Part 1171

An engineer made a time travel film and refused to explain it

Primer (film)

Primer is a 2004 independent science fiction film that Shane Carruth wrote, directed, produced, edited and scored, and also acted in, alongside David Sullivan. It follows the accidental discovery of time travel. It is known for a very low budget, an experimental plot structure, and technical dialogue Carruth declined to simplify.

which Carruth, a college graduate with a degree in mathematics and a former engineer, chose not to simplify for the sake of the audience

The refusal to translate is the whole appeal for this audience. The dialogue sounds like two contractors debugging a fault they do not yet have a name for, and the plot rewards the behavior a hard bug rewards: draw the diagram, replay it, argue about ordering. It is also a particular kind of founder story, one man with a mathematics degree holding down nearly every line of the credits, which reads to Hacker News as a proof that constraints are not the obstacle people claim.

DetailIt won the Grand Jury Prize Dramatic at the 2004 Sundance Film Festival.

225 points by iamwil 28 May 2010 91 comments

Also on the front page that day419 stories posted

1. #1What To Do With Your Millions291
2. #2I've Changed My Mind About The iPad249
3. #4Lessons learned from 13 failed software products175
4. #5Programming: Attitude Trumps Intelligence170
5. #6Ask HN: I sold my company last month for $5m. What do I do with the money?142

511 points for a four-digit number, posted with no explanation

6174

Wikipedia's article on the integer 6174. The summary the encyclopedia hands out is one sentence long: it is the natural number following 6173 and preceding 6175. Whatever reputation the number carries, that opening line does not say what it is.

6174 (six thousand, one hundred [and] seventy-four) is the natural number following 6173 and preceding 6175.

Submitted as a bare numeral, no framing, no pitch, which is a small dare and was taken as one. The site has a standing weakness for integers with a trick hidden inside them, and enough readers knew this one on sight to push it past a hundred comments. It finished fourth on a day led by an App Store commission ruling and an essay on AI training data, and ahead of OpenAI dropping its ban on military work.

DetailWikipedia's entire lead for 6174 says only that it follows 6173 and precedes 6175.

511 points by gone35 16 January 2024 102 comments

Also on the front page that day1148 stories posted

1. #1Show HN: I made a website to find best bus seat to avoid the sun while traveling963
2. #2US developers can offer non-app store purchasing, Apple still collect commission911
3. #3On being listed as an artist whose work was used to train Midjourney757
4. #5OpenAI drops ban on military tools to partner with The Pentagon371
5. #6TinyML: Ultra-low power machine learning370

The credit line nobody wants: killed by the thing you built

List of inventors killed by their own invention

Posted as “List of Inventors Killed By Their Own Inventions”

Wikipedia maintains a list of people whose deaths were caused by, or directly related to, a product, process, procedure, or other technological innovation that they themselves invented or designed.

people whose deaths were in some manner caused by or directly related to a product, process, procedure, or other technological innovation that they invented or designed

This is the extreme form of the postmortem every shipping engineer writes in their head, and the site that argues about testing in production found it irresistible. There is also the self-image it flatters and punishes at once: the inventor who believed the demo enough to stand in front of it. Any enumeration posted here turns into a crowdsourced audit of the enumeration, with people proposing additions and disputing the apocryphal ones, which is half the reason lists do well.

DetailTo qualify for the list, the death has to have been caused by or directly related to something the person invented or designed.

Also submitted as List of inventors killed by their own inventions.

109 points by Freebytes 2 September 2009 59 comments

Hacker News found it again on 28 Feb 2013, 19 Dec 2016, 6 Jun 2019, 7 Feb 2021.

Also on the front page that day300 stories posted

1. #1Dropbox's Summer 07 YC Application310
2. #2The bar for success in our industry is too low282
3. #3I bought a CD, not a licensing agreement132
4. #5Olark (YC S09) Brings Chat to Any Website - Whether You Own the Site or Not103
5. #6Why You Should Quit Your Job and Travel around the World94

How the Allies counted German tanks from captured gearboxes

German tank problem

Posted as “The German Tank Problem”

A problem in statistical estimation: given a set of items numbered 1 to N and a random sample of those numbers, estimate N. The article works it both ways, frequentist and Bayesian, and notes the two approaches give different answers. It is named for its wartime use, where Allied forces estimated the monthly rate of German tank production from the serial numbers on captured components.

This contrasted with conventional intelligence, which often overestimated Nazi output; this statistical approach yielded a highly accurate estimate.

A cheap statistic beat an expensive intelligence apparatus, and it worked because the enemy's own manufacturing discipline leaked the answer. Sequential identifiers as a side channel is something this crowd recognizes on sight, having shipped auto-increment primary keys in URLs and monotonic invoice numbers of their own. The estimator is small enough to derive on a napkin, and the frequentist versus Bayesian split guarantees the comment section has somewhere to go.

DetailThe sample came from ascending serial-number sequences attached to tank chassis, gearboxes, engines and wheels.

103 points by _pius 23 June 2009 18 comments

Hacker News found it again on 2 Mar 2011, 21 Feb 2014, 3 Dec 2016.

Also on the front page that day253 stories posted

1. #1Review my startup: Revizr. You haven't seen this before.131
2. #2Work smart, not hard: The seven habits of highly effective slackers127
3. #3The TED Augmented Reality Hoax124
4. #5PyGo Wave Server is here - play with the Waves now86
5. #6Four crowdsourcing lessons from the Guardian’s expenses-scandal experiment82

Two capacitors, one switch, and a paradox in plain circuit theory

Two capacitor paradox

Two identical capacitors sit in parallel with an open switch between them, one charged and one empty. Close the switch and charge moves until both sit at the same voltage, which, with equal capacitance, leaves each holding half the original charge at half the original voltage. Wikipedia files the whole thing as a counterintuitive thought experiment in electric circuit theory.

When a steady state is reached and the current goes to zero, the voltage on the two capacitors must be equal since they are connected together.

The setup is two capacitors and a switch, and that is precisely why it works: no exotic physics, no ambiguity in the statement, and a disagreement that can only be resolved by naming what the idealised model quietly left out. This is the site's favourite shape of problem, the one where the argument is not about the answer but about which simplification broke. It drew 169 comments, which for a textbook circuits exercise counts as a brawl.

DetailOnce the switch closes, each capacitor settles at charge Q/2 and half the voltage the charged one started with.

438 points by rathel 25 May 2020 169 comments

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The game whose first legal move is amending the rules

Nomic

Nomic is a game invented in 1982 by the philosopher Peter Suber in which play consists of proposing changes to the rules and voting on them. Suber built it to make an argument: in any system that allows its own rules to be amended, the rules can end up contradictory, or simply silent on what is permitted.

in any system where rule-changes are possible, a situation may arise in which the resulting laws are contradictory or insufficient to determine what is legal

Programmers recognise Nomic on sight as a self-modifying program with a voting scheduler bolted on, and the failure state Suber was pointing at is the one they meet in build systems, standards bodies and constitutions. The pleasure is that it is not a bug anyone can fix; it is a property of having the feature at all. Eighty-four comments arrived under a bare one-word title with no framing attached to help them along.

DetailNomic dates to 1982 and was designed by the philosopher Peter Suber.

242 points by eugeniodepalo 8 December 2012 84 comments

Hacker News found it again on 21 Jun 2009.

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Two envelopes, one obvious answer, and a calculation that disagrees

Two envelopes problem

A paradox in probability theory, also called the exchange paradox and descended from an older puzzle known as the necktie paradox. You are handed one of two identical envelopes, one containing twice the money of the other, and offered a swap before you look inside. Symmetry says switching is pointless; a plain expected-value calculation says switch, since you stand to double while risking only a halving.

Since the situation is symmetric, it seems obvious that there is no point in switching envelopes.

The appeal is structural rather than mathematical: a short chain of individually defensible steps that terminates somewhere unacceptable. That is the same shape as a subtle production bug, and readers here treat it the same way, by demanding to see the exact line where the reasoning goes wrong. The thread drew 88 comments against 112 points, a ratio that reliably marks an argument rather than an appreciation.

DetailOne envelope contains exactly twice what the other does, and the swap is offered before you inspect anything.

Also submitted as Two envelope problem.

112 points by atomon 6 August 2010 88 comments

Hacker News found it again on 14 Sep 2013, 30 May 2022.

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The 1991 broadcast that presented Lenin as, scientifically, a mushroom

Lenin was a mushroom

A televised hoax by the Soviet musician Sergey Kuryokhin and the reporter Sergey Sholokhov, broadcast on Leningrad Television on 17 May 1991. It took the form of an interview presenting supposed findings that Vladimir Lenin was in fact a mushroom.

an interview about the supposed findings that Vladimir Lenin was in fact a mushroom

What gets analyzed here is the delivery mechanism, not the joke. Kuryokhin borrowed the grammar of the late-Soviet television interview, its pacing and its air of sourced authority, and pointed it at an audience with no prior reason to expect that format to lie. Hacker News reads that the way it reads a well-built phishing page: the payload is absurd, the exploit is the trusted channel, and the interesting question is what in the viewer's model of the world had to be true for it to land.

DetailIt first aired on 17 May 1991 on Leningrad Television.

574 points by Smaug123 22 June 2016 178 comments

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A denial of service with no botnet and no flood, just a document

Billion laughs

Wikipedia gives this one sentence: in computer security, a billion laughs attack is a type of denial-of-service attack aimed at parsers of XML documents. That is the entire introduction. The mechanics sit in the body of the article rather than the intro, so the summary can only name the target.

This is the community's preferred class of exploit. There is no buffer overrun, no privilege escalation, nothing malformed; the input is a perfectly valid document, and the parser does the damage to itself by following the specification. It also generalises, and the thread ran to 63 comments, because every format with a substitution feature has a version of this sitting inside it waiting to be noticed. The day's number one story was a guide to the SSH config file, which is the same appetite approached from the friendly end.

DetailWikipedia's whole introduction is a single sentence, and it names only the target class: parsers of XML documents.

276 points by khet 20 October 2012 63 comments

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A listening device with no battery, no wires, and nothing to find

The Thing (listening device)

Posted as “The Thing”

The Thing, also called the Great Seal bug, was one of the first covert listening devices to use passive techniques to transmit an audio signal. It was concealed inside a gift the Soviet Union gave to W. Averell Harriman, the United States ambassador to the Soviet Union, on 4 August 1945. It was a tiny capacitive membrane connected to a quarter-wavelength antenna, with no power supply and no active components. Voices vibrated the membrane, which varied the capacitance the antenna saw, modulating a radio signal sent to it from an external transmitter; the NSA's term for that is illuminating a passive device.

The Thing consisted of a tiny capacitive membrane connected to a small quarter-wavelength antenna; it had no power supply or active electronic components.

This is the entire case for passive RF compressed into one object: the bug is inert until someone else spends the energy, and the article says outright that it was very hard to detect because it was very small and had no power supply. The article also calls it a predecessor of RFID, and that lineage is what keeps the thread going, since the same trick now lives in every access badge and toll transponder. Underneath the espionage there is the reduction itself, a microphone with no parts, which this audience admires more than any quantity of clever software.

DetailIt was hidden inside a gift the Soviet Union presented to the US ambassador, W. Averell Harriman, on 4 August 1945.

Also submitted as Thing (listening device).

599 points by cos2pi 11 June 2019 104 comments

Hacker News found it again on 3 Mar 2011.

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The archive file designed to freeze whatever tries to read it

Zip bomb

A zip bomb, also called a decompression bomb or zip of death, is a malicious archive built to crash or freeze the program that opens it. Older systems and programs are less likely to detect one. A common use is to knock out antivirus software, opening a path for more conventional malware.

It is often employed to disable antivirus software in order to create an opening for more traditional malware.

This is the purest adversarial object the format world produces: a perfectly valid archive, no memory corruption, no exploit chain, just the decompressor honoring its own specification until the machine gives out. Hacker News reads that as a lesson about trust boundaries rather than a prank, because every service that accepts user uploads has this problem and most discover it late. The detail that keeps threads going is the second-order use in the extract, disabling the scanner so that ordinary malware can walk in behind it.

DetailIt also goes by "zip of death", abbreviated ZOD.

342 points by takinola 5 October 2012 108 comments

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Colorless for a few seconds, then red, and the gold is gone

Aqua regia

Posted as “Hiding Nobel prizes in plain sight”

Aqua regia is nitric acid and hydrochloric acid mixed at an optimal molar ratio of 1:3. Freshly prepared it is colorless, then within seconds it turns yellow, orange or red as nitrosyl chloride and nitrogen dioxide form. Alchemists named it royal water because it dissolves noble metals such as gold and platinum while leaving many other metals unaffected, and the article notes it has been used to process or conceal gold into the modern era.

It was so named by alchemists because it can dissolve noble metals, such as gold and platinum, while leaving many other metals unaffected.

Read the submitted title again: hiding Nobel prizes in plain sight. What went to the front page was not a chemistry stub but a hiding place, a reagent that converts a distinctive physical object into an anonymous orange liquid nobody thinks to search. The selectivity is what makes it elegant rather than merely destructive; it takes the gold and leaves many other metals alone, which is the same reason a good filter is the interesting part of any pipeline.

DetailThe optimal mix is one part nitric acid to three parts hydrochloric acid, by moles.

220 points by Muzza 1 March 2011 52 comments

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The interception room an AT&T technician made public in 2006

Room 641A

Room 641A is a telecommunication interception facility that AT&T operated for the National Security Agency as part of an American mass surveillance program. It began operating in 2003. Its purpose was revealed publicly in 2006 by AT&T technician Mark Klein.

Room 641A is a telecommunication interception facility operated by AT&T for the U.S. National Security Agency, as part of an American mass surveillance program.

A room number is an extremely efficient way to make an abstract program concrete: not 'surveillance' but a door, a floor, and a company that did the installation. The article also has the shape this community respects most, which is a working technician who understood exactly what the cabling implied and said so out loud, years before anyone was ready. In June 2013 it was being reread as prior art rather than history.

DetailThe facility ran for three years before Mark Klein made it public in 2006.

Why that weekThis landed on 9 June 2013, days after the first Guardian NSA stories and on the day Edward Snowden identified himself publicly. Four of the day's other five top stories were the NSA backdoor key in Lotus Notes, the secret court opinion behind PRISM, 'Why Privacy Matters Even if You Have Nothing to Hide', and the likely criminal probe into the leaks. A 2006 disclosure was being read as the earlier chapter of that week.

248 points by llambda 9 June 2013 44 comments

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Stuck in the wrong orbit: HN blamed a patent, Wikipedia blames a stage

AMC-14

Posted as “Satellite killed by trajectory patent”

AMC-14 is a communications satellite built by Lockheed Martin on the A2100 bus, intended for Dish Network service from 61.5 degrees West. It launched from Baikonur on 14 March 2008, and a malfunction of the Briz-M upper stage left it in an unusable orbit. Over six months it was maneuvered into a geosynchronous orbit near 35 degrees East, inclined.

The satellite was placed in an unusable orbit, following a malfunction of the Briz-M upper stage.

It arrived titled "Satellite killed by trajectory patent," and that framing, not the hardware, is what pulled 195 points and 71 comments. Patent overreach was the community's standing grievance, and the idea of a patent standing between a stranded spacecraft and the maneuver that would save it is that grievance rendered in metal. Worth noticing that the encyclopedia entry records only the upper stage failure and the long crawl to a usable orbit, so the accusation lived entirely in the thread.

DetailIt lifted off at 23:18:55 UTC on 14 March 2008 from Site 200/39 at Baikonur.

195 points by frabcus 20 May 2012 71 comments

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A thousand hibernating bats, each carrying a timed incendiary

Bat bomb

Bat bombs were an experimental American weapon of the Second World War: a bomb-shaped casing holding over a thousand compartments, each with a hibernating Mexican free-tailed bat and a small timed incendiary attached to it. Dropped at dawn, the casing was to parachute, open, and scatter bats that would roost in eaves and attics across a 20 to 40 mile radius, with the timers firing later, inside the wood and paper construction of the Japanese cities that were the intended target. The United States Navy took control in August 1943 under the code name Project X-Ray.

The bomb consisted of a bomb-shaped casing with over a thousand compartments, each containing a hibernating Mexican free-tailed bat with a small, timed incendiary bomb attached.

Strip the horror off and it is a delivery architecture, and a clever one: a thousand self-routing payloads that find precisely the inaccessible interiors a falling bomb cannot reach. This audience reads it the way it reads a distributed-systems design, admiring the routing before flinching at the cargo. A payload that hibernates, wakes on its own schedule, and then picks its own destination is also a specification problem anyone who has shipped software recognizes immediately.

DetailOne casing held over a thousand bats, expected to disperse across a 20 to 40 mile radius before their incendiaries fired.

252 points by The_Fox 8 November 2014 40 comments

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Some integers are contraband, and the law has to say so out loud

Illegal number

Posted as “Illegal prime”

An illegal number is a number representing information that is illegal to possess, utter, propagate, or otherwise transmit in some jurisdiction. The reasoning is one step long: any piece of digital information can be written as a number, so a prohibition on the information carries over to the number itself.

An illegal number is a number that represents information which is illegal to possess, utter, propagate, or otherwise transmit in some legal jurisdiction.

The submission ran under the title "Illegal prime", which is the sharpest form of the joke: take banned bits, find an encoding of them that happens to be prime, and hand the legal system an object that is simultaneously a criminal artifact and a fact about arithmetic. This community collects exactly these collisions between formal systems and legal ones, because the law has to answer and cannot answer well. It is also a reductio you can actually run rather than merely assert.

DetailThe definition names four ways a number can get you in trouble: possessing, uttering, propagating, or otherwise transmitting it.

Also submitted as Illegal prime.

152 points by niyazpk 11 January 2010 76 comments

Hacker News found it again on 28 Oct 2012, 17 Oct 2013, 30 Jul 2014, 22 Nov 2016, 27 Apr 2018, 12 Apr 2021.

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Twenty-five buzzes a minute on 4625 kHz, purpose never disclosed

UVB-76

Posted as “The Buzzer”

UVB-76, nicknamed the Buzzer, is a shortwave station transmitting in upper sideband mode on 4625 kHz, a wavelength of 64.8 metres. It broadcasts a short, monotonous buzz tone about 25 times a minute, 24 hours a day, and sometimes the buzz is interrupted by a voice transmission in Russian. Its true purpose has never been revealed; the best-supported theory ties it to a military command network for the Leningrad Military District.

While its true purpose has never been revealed, the transmission is not related to the Dead Hand system, despite being sometimes referred to as Doomsday Radio.

A channel that transmits around the clock and says almost nothing, that anyone with a receiver can check for themselves right now, and that no official body will explain, is an undocumented protocol you can sniff from your own desk. The community listens to it the way it debugs, ignoring the steady state and waiting for the exception path. The article's flat negative is the part that sticks: the signal has been interrupted and stopped many times, and nothing was ever launched as a result.

DetailThe buzz repeats about 25 times per minute, 24 hours a day, on 4625 kHz.

227 points by tshtf 5 June 2010 55 comments

Hacker News found it again on 25 Nov 2020.

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A calendar that opens in 3001 CE and closes with proton decay

Timeline of the far future

The article gathers what several fields can say about events past the present: astrophysics on how stars form and die, particle physics, evolutionary biology, plate tectonics, sociology. Its timelines begin at the start of the 4th millennium and run to the remotest reaches of future time. Along the way it flags the unresolved questions, including whether humans go extinct, whether Earth survives the Sun becoming a red giant, and whether proton decay ends all matter.

These timelines begin at the start of the 4th millennium in 3001 CE, and continue until the furthest and most remote reaches of future time.

Read as an artifact rather than an essay, this is a sorted list whose keys run from the next millennium out toward the possible end of all matter, which is the sort of thing engineers enjoy for its own sake. It also offers the specific pleasure of watching every human concern get pushed into the first row and then off the edge. No calls to action, no takeaway, just monotonically increasing timestamps.

DetailThe timelines start at 3001 CE, the opening of the 4th millennium, and go up from there.

294 points by microtherion 6 May 2012 88 comments

Hacker News found it again on 18 Jul 2018, 17 May 2020.

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NOAA sped these up 16x and still could not name them

List of unexplained sounds

A running catalogue of sounds that are currently unidentified, or were unidentified until someone worked out the source. Every NOAA sound file on the page has been sped up by at least a factor of 16, which condenses the clip and raises it from infrasound into a more audible range.

sped up by at least a factor of 16 to increase intelligibility by condensing them and raising the frequency from infrasound to a more audible and reproducible range

An unsolved-signal list with the primary data attached invites exactly what this site enjoys: listen, form a hypothesis, be wrong in public. The playback note is itself an engineering detail, a reminder that the phenomenon and the instrument are entangled and that you are hearing a transform, not the thing. Best of all, entries move from the unexplained column to the explained one over time, so the page behaves like a bug tracker that occasionally closes a ticket.

DetailThe NOAA clips are played back at 16x or faster because the originals sit down in infrasound.

280 points by rsiqueira 17 June 2012 75 comments

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Heard since the late 1980s at the wrong frequency, never once seen

52-hertz whale

An individual whale of unidentified species calls at 52 hertz in the north Pacific, well above the 10 to 39 Hz of blue whales and the 20 Hz of fin whales. It has only ever been detected on hydrophones; the animal itself has never been sighted. Its calls have been picked up since the late 1980s in a pattern matching the migration of those two species.

Described as the "world's loneliest whale", it appeared to be the only individual emitting a whale call at this frequency.

Decades of clean instrument data, a signal nobody can attribute, and no visual confirmation is the exact profile of the anomalies this site enjoys, just rendered in biology instead of radio astronomy. The page also hands the thread its rebuttal: the last line reports recordings of a second 52-hertz whale, heard elsewhere at the same time, which quietly undercuts the loneliness story everyone came for. Reading past the headline to the correction is the sport.

DetailBlue whales call at 10 to 39 Hz and fin whales at 20 Hz; this one calls at 52.

299 points by iso-8859-1 27 February 2016 89 comments

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Write a whole essay without ever using the verb 'to be'

E-Prime

Posted as “English-Prime - English without "is"”

E-Prime is a restricted form of English in which the writer avoids every form of the verb to be. That rules out be, being, been, am, is, are, was and were, plus the contractions built from them, down to isn't, aren't, ain't, twas and I'm. Some scholars claim the constraint clarifies thinking and strengthens writing; others doubt it does anything useful.

Some scholars claim that E-Prime can clarify thinking and strengthen writing, while others doubt its utility.

This is a keyword removed from a language, paired with a claim that the removal improves the output. That reads to Hacker News as a compiler flag applied to English: the rule is strict enough to check mechanically, and the benefit stays arguable forever. The obvious move is to try writing a comment in it, which is the same instinct that makes people attempt a puzzle in a language they cannot read.

DetailThe prohibition reaches into contractions, so isn't, aren't, ain't, twas and I'm are all disallowed.

108 points by silentbicycle 5 January 2009 76 comments

Hacker News found it again on 7 Dec 2015, 26 May 2021.

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Two researchers coined a word for the smell of rain, in Nature, 1964

Petrichor

Posted as “The official term for the smell after it rains”

Petrichor is the earthy scent associated with rain falling on dry soil or rock. Two Australian researchers, Isabel Joy Bear and Richard Grenfell Thomas, introduced the term in a 1964 paper in Nature. They used it for an odour released from rock or soil after dry conditions, once moisture reaches it.

Bear and Thomas used the term for an odour released from rock or soil materials after dry conditions when they are exposed to moisture.

There is a particular satisfaction in learning that something everyone has noticed and nobody has labelled turns out to have a formal name, filed in Nature, with two authors attached. A community that will spend an afternoon arguing over what to call a variable is unusually susceptible to a good coinage. The word also promises a mechanism: the smell is not the weather, it is the ground giving something up when it gets wet.

DetailThe word was introduced in a 1964 Nature paper by Isabel Joy Bear and Richard Grenfell Thomas.

148 points by scorxn 21 December 2009 36 comments

Hacker News found it again on 27 Dec 2022.

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A word that occurs three times, then nowhere else, ever

Epiousion

Posted as “Epiousios”

Epiousion is a Koine Greek adjective from the Lord's Prayer, in the line normally rendered as give us today our daily bread. It occurs only three times, at Matthew 6:11, Luke 11:3 and in the early Christian treatise Didache, always inside the same prayer, so there is no independent context to read it against. Daily is the traditional translation and most scholars now reject it, in part because all the other New Testament passages translated daily also carry the word hemera.

Because the word is used nowhere else, its meaning is unclear.

This is a decoding problem with no second sample, which is catnip for people who argue about ambiguous grammars and underspecified protocols. The candidate readings run from daily to supersubstantial, the choice is unresolvable from the data, and two millennia of downstream text depend on which branch you take. The clinching argument is an argument from absence, that a genuine daily would have brought hemera along with it, and this crowd finds that shape of reasoning more convincing than any amount of tradition.

DetailIt is a tris legomenon, appearing exactly three times: Matthew 6:11, Luke 11:3 and the Didache.

Also submitted as Epiousios.

538 points by benbreen 13 September 2021 201 comments

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Eight repetitions of one word, and it parses as English

Buffalo buffalo Buffalo buffalo buffalo buffalo Buffalo buffalo

The sentence is grammatically correct English built entirely from repetitions of one word, and it is the standard demonstration of how homonyms and homophones produce lexical ambiguity. Wikipedia offers a semantically equivalent version that preserves the original word order: Buffalonian bison whom other Buffalonian bison bully also bully Buffalonian bison. It has been discussed in the literature since 1967, when it appeared in Dmitri Borgmann's Beyond Language: Adventures in Word and Thought.

Buffalonian bison [whom other] Buffalonian bison bully [also] bully Buffalonian bison.

Ambiguity is a parsing problem before it is a joke, and this is the adversarial input: a string that type-checks against the grammar while defeating every human reader on the first pass. People who write tokenizers and argue about ambiguous productions treat it as a test case rather than a curiosity. The submission was the bare sentence with nothing attached, and it still pulled 69 comments.

DetailIt has circulated in print since 1967, when Dmitri Borgmann included it in Beyond Language: Adventures in Word and Thought.

174 points by roundsquare 3 February 2010 69 comments

Hacker News found it again on 8 May 2016, 7 Sep 2023.

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One volunteer, one two-word phrase, thousands of edits

User:Giraffedata/comprised of

Posted as “Wikipedia user edits over 90k uses of “comprised of””

The user page where the editor Giraffedata explains the removal of the phrase "comprised of" from thousands of Wikipedia articles, and why the edit summaries usually point back to it. The opening is preemptively defensive, steering anyone who arrived already certain the project is wrong toward the section on common misunderstandings before they start typing.

I have edited thousands of articles so that they do not contain the phrase "comprised of".

There is a specific admiration in this community for someone who selects one narrow, unglamorous, arguably incorrect task and then executes it at a scale requiring either automation or an unreasonable supply of patience. The submission drew 707 comments against 437 points, from a crowd that argues about tabs, trailing commas and whether prescriptivism is a category error, and that had been handed a live specimen who anticipated their objections in advance. It is the closest thing Wikipedia has to a long-running daemon with opinions.

DetailThe page heads off its critics with a section titled Common misunderstandings of my thoughts and my work.

437 points by shaklee3 6 May 2023 707 comments

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Grammatical sentences that make your parser back up and retry

Garden-path sentence

Posted as “Garden path sentence”

A garden-path sentence is grammatically correct but opens in a way that lures the reader into the wrong parse, so the sentence seems to break and has to be read again before it makes sense. The name comes from being led up the garden path, meaning deceived. Fowler, in A Dictionary of Modern English Usage in 1926, described the effect as unwittingly laying a false scent.

In A Dictionary of Modern English Usage (1926), Fowler describes such sentences as unwittingly laying a "false scent".

Anyone who has written a parser recognises the failure instantly: a human hitting a case that requires backtracking, complete with the wasted work and the visible stall. These are inputs that are valid under the grammar and still crash the reader, which is precisely the category this crowd collects. It also flatters a suspicion the site enjoys holding, that natural language is a badly specified protocol shipped without error handling.

DetailFowler was describing these in 1926, as sentences that unwittingly lay a false scent.

Also submitted as Garden path sentence.

124 points by niyazpk 9 July 2010 42 comments

Hacker News found it again on 23 Nov 2015.

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Fiction's first trip to outer space was written in the 2nd century

A True Story

A long novella or short novel written in the second century AD by the Syrian author Lucian of Samosata, satirizing outlandish tales reported in earlier ancient sources, especially ones that presented mythical events as if they were true. It contains travel to outer space, alien lifeforms, and interplanetary warfare, which makes it the earliest known work of fiction to do so. Scholars still argue over whether it counts as science fiction, fantasy, satire, or parody.

It is the earliest known work of fiction to include travel to outer space, alien lifeforms, and interplanetary warfare.

Origin stories are this community's native genre, and the origin here is better than the usual one: the first space voyage in literature was written as a parody of writers who reported invented marvels as fact. That the genre begins in bad faith, aimed at credulous readers, is a joke HN can appreciate from long experience with confident claims. The title alone does most of the work, since the whole thing is invented.

DetailLucian of Samosata wrote it in the second century AD, and it is his best-known work.

525 points by benbreen 15 October 2018 72 comments

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A banknote worth nothing, handed to officials who ask for bribes

Zero-rupee note

Posted as “Zero Rupee Note”

The zero-rupee note is an imitation Indian banknote, styled after the old 50-rupee note, created by the NGO 5th Pillar as a tool against systemic political corruption. Citizens hand one over in protest when an official demands a bribe for a service that is supposed to be free. Since 2007 more than 2.5 million had been distributed as of August 2014, and thousands still go out monthly.

The notes are "paid" in protest by angry citizens to government functionaries who solicit bribes in return for services which are supposed to be free.

The design carries the entire argument. Passing a worthless note in the exact gesture of paying a bribe turns a private extortion into a public accusation without anyone having to say the word, and it gives the person with no leverage something to physically do. Hacker News is drawn to interventions that are cheap, self-explanatory and scale by printing more paper rather than by raising a round, and the fact that the notes were still in current use years on, thousands a month, is what separates this from the usual clever-idea post.

Detail5th Pillar had distributed over 2.5 million notes as of August 2014.

Also submitted as Zero rupee note.

771 points by aaronharnly 3 June 2019 235 comments

Hacker News found it again on 25 Feb 2024.

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A coastal city on the Persian Gulf that the sea walked away from

Ur

Ur was a major Sumerian city-state in southern Mesopotamia, at the site now called Tell el-Muqayyar in Iraq. It dates from the Ubaid period around 3800 BC and appears in written history as a city-state from the 26th century BC, with Mesannepada as its first recorded king. Once a coastal city near the mouth of the Euphrates on the Persian Gulf, the site now sits well inland, 16 km southwest of Nasiriyah.

The temple was built in the 21st century BC, during the reign of Ur-Nammu and was reconstructed in the 6th century BC by Nabonidus, the last king of Babylon.

The appeal is the depth of the stack. A king in the 6th century BC carried out a reconstruction of a temple built in the 21st century BC, which is legacy maintenance on a system already fifteen centuries old, and a useful thing to remember while arguing about whether ten-year-old code is unmaintainable. The moved coastline lands the same way: the infrastructure stayed put and the requirements relocated. Submitted as two letters, with no case made at all.

DetailThe ziggurat's shrine to the moon god Nanna was excavated in the 1930s.

509 points by tosh 12 November 2022 103 comments

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Signed by dozens of governments, ratified by one, in force nowhere

Anti-Counterfeiting Trade Agreement

Posted as “ACTA will force border searches of laptops, smartphones for pirated content”

ACTA was a multilateral treaty meant to set international standards for intellectual property enforcement, covering counterfeit goods, generic medicines, and online copyright infringement, and to create a governing body outside the WTO, WIPO, and the UN. Eight countries signed in October 2011; Mexico, the European Union, and 22 EU member states followed in 2012. Only Japan ratified it, six ratifications were required, and it never entered into force.

a multilateral treaty for the purpose of establishing international standards for intellectual property rights enforcement that did not enter into force

The submitted title was about border searches of laptops and phones, which is the moment a trade treaty turns into a threat model. What held attention was the structure of the thing: an enforcement regime negotiated outside every existing forum, with industry bodies named in the article as having shaped its agenda. This is the site doing what it does with any rule it dislikes, reading the actual mechanism rather than the summary of it.

DetailSix ratifications would have brought ACTA into force; it received exactly one, from Japan.

Why that weekA real peg, but a general one. This went up on 22 January 2012, four days after the SOPA blackout and three days after the Megaupload seizure, and the submitted title frames ACTA as the next place that fight would be fought. No ACTA-specific announcement that week shows up in the record. The same-day front page is thinner support than it first looks: one other enforcement story, US customs blocking DVDs that depict insurrection, sat at rank five, and a "Kill Hollywood" pitch was at rank six, outside the top five; the rest of the day was waking up at 5am to code, Amazon Studios, and an icon set.

412 points by nextparadigms 22 January 2012 191 comments

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The area code that was never meant to ring for you

Area code 710

Area code 710 is a special code in the North American Numbering Plan, reserved for the United States federal government in 1983 for emergency services. Since 1994 it has provided authorized personnel with access to the Government Emergency Telecommunications Service, reaching through Canadian local exchange carriers and cellular and PCS networks. Before that it was a Service Access Code in the Teletypewriter Exchange Service covering the northeastern United States.

It was reserved for the federal government of the United States in 1983 for emergency services.

The phone network is this site's favorite legacy system, and 710 is a live fragment of it: an entire area code fenced off for one government service, with a priority-access layer bolted on top of numbering plumbing built for teletypes. The appeal is the same as an undocumented endpoint that still answers when you call it. It also demonstrates the thing every maintainer already knows, which is that address space gets recycled rather than designed.

DetailReserved in 1983, the code did not carry GETS access until 1994.

356 points by raldi 10 June 2017 81 comments

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Microsoft's Wi-Fi portable toilet: announced, denied, then un-denied

ILoo

The iLoo was a cancelled Microsoft project for a Wi-Fi Internet-enabled portable toilet, intended to debut at British summer festivals and specified with wireless broadband, an adjustable plasma screen, a membrane wireless keyboard, a six-channel speaker system, a second screen and keyboard on the outside, and a guard. It was pitched as the next in a series of MSN UK initiatives that already included MSN Street, MSN Park Bench and MSN Deckchair. MSN UK announced it on April 30, 2003; it was widely ridiculed, declared a hoax by Microsoft on May 12, and described the next day as real but cancelled.

a membrane wireless keyboard, a six-channel speaker system, and toilet paper embossed with popular web site addresses

The engineering is beside the point; the failure is a communications stack losing consistency in under 24 hours, which is a category of disaster this audience watches with professional interest. There is also a quiet control case buried in the entry: the Chaos Computer Club really does put network distribution gear in toilet stalls at its camps, with no brand to promote and no press release to retract.

DetailMicrosoft called the project a hoax on May 12, 2003, then said the next day that it had been real and merely cancelled.

354 points by vezzy-fnord 23 July 2015 56 comments

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The job description that outlasted rope, grain and the wiring

Ship's cat

Cats have sailed on trading, exploration and naval ships since ancient times, and the article is unsentimental about why: rodent control. Rats aboard chew rope and woodwork, eat the crew's food and the cargo, and more recently go after electrical wiring. They also carry disease, which is a particular problem on a vessel at sea for long stretches.

Rat fleas are carriers of plague, and rats on ships were believed to be a primary vector of the Black Death.

What holds the attention is a job description that outlasted every change in the technology underneath it. The threat model stayed fixed from antiquity to the wiring loom, the asset being protected went from grain sacks to shipboard electronics, and the mitigation never needed a rewrite. gwern posted it under its bare title on a day the front page was otherwise split between Apple CarPlay and the smoking crater of Mt. Gox, and it still took third.

DetailThe article updates the damage list for the modern era: ropes, woodwork, and more recently, electrical wiring.

277 points by gwern 3 March 2014 72 comments

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Coca-Cola made a colorless batch to order for a Soviet marshal

White Coke

White Coke was a clear variant of Coca-Cola produced in the 1940s at the request of Georgy Zhukov, Marshal of the Soviet Union. The recipe was otherwise untouched: the flavor was the same as the original, and the only difference was the absence of caramel coloring.

was a clear variant of Coca-Cola produced in the 1940s at the request of Marshal of the Soviet Union Georgy Zhukov

A bespoke production run by a large American company for one customer on the far side of an emerging Cold War is the kind of supply-chain exception this audience finds funnier than most actual news. The appeal is how narrow it is: not a policy, not a scandal, a single manufacturing variance granted to a single man, and the variance removes the one property that made the product recognisable. It finished fourth on a day whose top five also held Linus Torvalds on acting professionally, an Ask HN from a quadriplegic user asking for help with security, the EFF suing the NSA, and a Snowden email exchange.

DetailThe only change from standard Coca-Cola was dropping the caramel coloring; the flavor was unchanged.

478 points by annapowellsmith 17 July 2013 236 comments

Hacker News found it again on 26 Nov 2015.

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100,000 stones, laid at the last place a person chose freely

Stolperstein

A Stolperstein is a ten-centimetre concrete cube topped with a brass plate carrying the name and life dates of a victim of Nazi extermination or persecution. Gunter Demnig began the project in 1992, and it aims to place each stone at the last place the person chose freely to reside, work or study, with exceptions possible case by case. Most commemorate Jewish victims; the rest span Sinti and Romani people, Poles, homosexuals, disabled people, Jehovah's Witnesses, Communist and Social Democratic party members, resisters, deserters and many other categories.

As of June 2023, 100,000 Stolpersteine have been laid, making the Stolpersteine project the world's largest decentralized memorial.

The design is the argument: no central monument, no pilgrimage site, just a hundred thousand nodes installed one at a time, which makes it immediately legible to people who think in distributed systems. The article's own phrase, world's largest decentralized memorial, is the hook. The second thing that lands is the addressing scheme, a memorial keyed to a place the person picked rather than the place they were killed.

DetailEach marker is a ten-centimetre concrete cube, and Gunter Demnig started the project in 1992.

445 points by dschuessler 18 June 2022 170 comments

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Paraffin heaters at the start; 74,117 people by the end of 2016

Mondragon Corporation

Mondragon Corporation is a federation of worker cooperatives in the Basque region of Spain, founded in the town of Mondragon in 1956 by Father Jose Maria Arizmendiarrieta and a group of his students at a technical college he had founded. Its first product was paraffin heaters. It is the leading business group in the Basque Country and the seventh-largest Spanish company by asset turnover, working across finance, industry, retail and knowledge.

Its first product was paraffin heaters.

This is the article people reach for when the recurring argument about ownership starts, because it is not a manifesto but an operating firm with a payroll and a turnover ranking, which is harder to wave off. 283 comments against 442 points is the ratio of a fight, and the fight is whether a structure with no outside shareholders survives past the size where the founders can still see everyone. Its return to the front page in 2026 suggests nobody has closed the question.

DetailAt the end of 2016 it employed 74,117 people across 257 companies and organizations.

442 points by taurath 10 February 2020 283 comments

Hacker News found it again on 28 Jul 2026.

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A list of businesses still trading, filed under "Before 1300"

List of oldest companies

Posted as “List of oldest companies: Before 1300”

Every entry here is a company that has kept operating, in whole or in part, since the day it was founded. The scope rule is strict: for-profit enterprises only, with associations and educational, government, and religious organizations excluded. It reached Hacker News under the title "List of oldest companies: Before 1300", aimed at the earliest stratum of the list. The intro itself names no companies and gives no dates.

the brands and companies which remain operating (either in whole or in part) since inception

Startups are a genre organised around speed, and this is the opposite reading: a roster whose defining achievement is that nobody ever shut them down. The exclusions do the real work, because removing churches, universities, and states removes nearly everything else that lasts that long, leaving the rarest thing on the list, a plain commercial business that simply kept trading. The hedge "in whole or in part" is also catnip to a crowd that will happily spend 198 comments deciding whether a firm that changed owners, trade, and country is still the same firm.

DetailThe list counts for-profit firms only: associations, schools, governments, and religious bodies are excluded.

416 points by aleyan 19 January 2018 198 comments

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Mensalão and Car Wash, then an AI pointed at public spending

Operation Serenata de Amor

Posted as “Operation Serenata de Amor – An AI project to analyze public spending in Brazil”

Operation Serenata de Amor is an artificial intelligence project built to analyze public spending in Brazil. It has been funded by a recurrent financing campaign since September 7, 2016. It came in the wake of major misappropriation scandals in the country, including the Mensalão scandal and what was revealed in the Operation Car Wash investigations.

Oversight here is a project rather than an agency: it runs on a recurring financing campaign instead of a budget line, and it aims a model at public spending in a country whose recent misappropriation scandals are the stated reason it exists. That is where this community's civic instinct sits, in the gap between institutions expected to audit themselves and a supporter-funded effort that simply built the tool. It drew 110 comments on 342 points, the ratio you get when the argument is about the institution rather than the code.

DetailThe project has been funded by a recurrent financing campaign since September 7, 2016.

342 points by dorfsmay 6 March 2018 110 comments

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Sheldon Wolin's 2003 word for a democracy managed by corporations

Inverted totalitarianism

Inverted totalitarianism describes a theoretical system in which economic power, corporations in particular, exerts subtle but substantial control over something that still looks democratic from outside. The theory predicts a drift toward powerlessness and political apathy. Sheldon Wolin coined the term in 2003 for what he saw emerging in the United States, which he called a managed democracy.

Inverted totalitarianism is a theoretical system where economic powers like corporations exert subtle but substantial power over a system that superficially seems democratic.

Political threads here usually collapse, and this one drew 158 comments instead, because the frame is legible to people who debug systems: the formal interface is unchanged while control quietly migrates elsewhere, and nobody has to break a rule for the outcome to change. Wolin names a failure mode rather than a villain, and a failure mode is something this crowd will pull apart for a full day. The "inverted" qualifier does real work too, since it concedes the differences from the classical version instead of shouting past them.

DetailWolin coined the term in 2003, describing the United States as a managed democracy.

240 points by pikachu_is_cool 14 December 2013 158 comments

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A money transfer network whose collateral is honour

Hawala

Hawala is a popular and informal value transfer system based on the performance and honour of a huge network of money brokers. It originated in India as havālā or huṇḍī, and carries other names across the regions that use it: ḥavâleh in Persian, xawala or xawilaad in Somali.

a popular and informal value transfer system based on the performance and honour of a huge network of money brokers

A value transfer system with no clearing house, no settlement rail and no central ledger, held together by the performance and honour of its brokers, is a design people here usually only sketch on a whiteboard. This one runs in the world, spread across a network large enough that there is no obvious place to switch it off. The word also arrives pre-loaded for a lot of readers, who will have met it in counterterrorism coverage long before they met it in anything about payments.

DetailOne system, many names: huṇḍī in India, ḥavâleh in Persian, xawala or xawilaad in Somali.

200 points by robbiet480 4 November 2013 55 comments

Hacker News found it again on 19 Apr 2009.

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HN came for a 75-word employee handbook and got a shoe store

Nordstrom

Posted as “Nordstrom's 75-word employee handbook”

The encyclopedia entry for an American upmarket department store chain, headquartered in Seattle and founded in 1901 by John W. Nordstrom and Carl F. Wallin. It covers the move from shoes into clothing, the launch of the off-price Nordstrom Rack division, and the competitors on both sides of that split. Neither the summary nor the article says anything about the handbook.

The original store operated exclusively as a shoe store, and a second location opened in 1923.

A 75-word handbook is the founding text for a whole management posture: hire adults, then stop writing rules at them. A site full of people drafting their first company policy doc treats it as an existence proof that the short version can work at scale, and then spends the thread arguing about whether it survives contact with a workforce in the tens of thousands. The Wikipedia page was the anchor rather than the payload, which is its own small lesson about how links get chosen.

DetailFounded in 1901 as a shoe store, the chain did not begin selling clothing until 1963.

200 points by j_baker 25 October 2010 68 comments

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Twenty-two years, one hammer, one chisel, one road through a ridge

Dashrath Manjhi

Posted as “The man who singlehandedly carved a road through a mountain”

Dashrath Manjhi was an Indian laborer from Gehlaur village, near Gaya in Bihar, who cut a path through a ridge of hills with hand tools, after his wife fell and died of injuries because the ridge blocked easy access to a nearby hospital. The path he carved is 110 metres long, 9.1 metres wide, and 7.7 metres deep. It took 22 years and collapsed a 55 km journey to 15 km.

He is best known for carving a 110-metre-long (360 ft), 9.1-metre-wide (30 ft), and 7.7-metre-deep (25 ft) path through a ridge of hills using only a hammer and a chisel

Brute force is not usually a compliment here, but brute force applied to correctly identified requirements is the highest one available. The measurements do the persuading: this is a story with a before number, an after number, and a duration, which the site trusts far more than sentiment. There is also the uncomfortable systems reading underneath, that the shortest path between a village and a hospital existed the whole time and no institution had built it.

DetailThe path shortened travel between the Atri and Wazirganj blocks of Gaya district from 55 km to 15 km.

483 points by wr1472 22 September 2012 96 comments

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The passenger list happened to include an orthopaedic surgeon

Angus Wallace

Posted as “In-flight surgery with a coat-hanger and silverware”

William Angus Wallace, born 31 October 1948, is a Scottish orthopaedic surgeon and Professor of Orthopaedic and Accident Surgery at the University of Nottingham. He became publicly known for a life-saving operation he performed with improvised equipment aboard a British Airways flight in 1995, and later for treating Wayne Rooney before the 2006 FIFA World Cup.

He came to widespread public notice for a life-saving surgery he performed using improvised equipment on a British Airways flight in 1995

The submitter led with the coat hanger and the silverware rather than the surgeon's name, which is the correct instinct for this audience: the story is a hard problem solved with whatever was in scope. It belongs to the same shelf as Apollo 13 and the 3am production fix, where expertise is real but the tooling is absent and the constraint is not negotiable. 707 points and 209 comments for a biography with a three-sentence lead.

DetailThe same surgeon treated Wayne Rooney ahead of the 2006 FIFA World Cup.

707 points by minding 17 March 2022 209 comments

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Out of fuel at 41,000 feet, landed on a racetrack, flew until 2008

Gimli Glider

Air Canada Flight 143, a Boeing 767 flying Montreal to Edmonton on 23 July 1983, ran out of fuel midway because the fuel gauge was not operating and the tanks had been underfilled from an incorrect calculation. The crew glided it from 41,000 feet to an emergency landing at a former Royal Canadian Air Force base in Gimli, Manitoba that had been converted into a racetrack. Nobody was seriously hurt, the damage to the aircraft was minor, and it was repaired and stayed in service until 2008.

an emergency landing at a former Royal Canadian Air Force base in Gimli, Manitoba, which had been converted to a racetrack, Gimli Motorsports Park

Every link in the chain is a line item from a postmortem anyone here has written: a sensor type with high failure rates, the only available replacement also nonfunctional, a logged problem the maintenance crew later misunderstood before switching off the backup, a manual workaround with a dripstick, and a volume-to-mass conversion done in the wrong units. The pounds-versus-kilograms detail gets the headlines, but the argument in the 198 comments was about the sequence, because no individual step was unreasonable. The coda is what makes it stick: they fixed the plane and it went back to work for another twenty-five years.

DetailThe 767 glided from 41,000 feet (12,500 m) and, once repaired, flew on until its retirement in 2008.

385 points by numlocked 18 December 2016 198 comments

Hacker News found it again on 23 Oct 2009, 1 May 2014.

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Three balloons, one failed attempt, eight people over the border

East Germany balloon escape

On 16 September 1979, eight people from two families crossed at night from East Germany into West Germany in a homemade hot air balloon. It took more than a year and a half of preparation, three different balloons and various modifications. An earlier attempt failed and alerted the East German authorities to the plot, but the police could not identify the escapees before the second flight two months later.

The failed attempt alerted the East German authorities to the plot, but the police were unable to identify the escapees before their second, successful flight two months later.

Read as an engineering project it has the full set: iteration across three balloons, an unforgiving constraint, and an adversary who is put on notice by your failed test. The first attempt did not merely fail, it leaked, and the families went again two months later while the authorities were still trying to work out who they were. 301 comments is what a story gets when it is a build log and a manhunt at once.

DetailEight people from two families flew out on 16 September 1979 after more than eighteen months of work and three balloons.

724 points by robertvc 16 January 2026 301 comments

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He ate a meal meant for fifteen and was still underweight

Tarrare

Tarrare was a French showman, soldier, and spy of the late eighteenth century, constantly hungry and able to eat vast amounts of meat. Turned out of the family home as a teenager, he performed by swallowing corks, stones, live animals, and a whole basketful of apples, then joined the French Revolutionary Army, where quadrupling the standard ration still left him starving. He became the subject of a series of medical experiments to test his eating capacity, and General Alexandre de Beauharnais later employed him as a courier.

he ate a meal intended for 15 people in a single sitting, ate live cats, snakes, lizards, and puppies, and swallowed eels whole without chewing

The article reads like a bug report against a human metabolism: escalating test cases, careful notes, no root cause found. What keeps people reading is not the eating, it is that he stayed underweight and showed no sign of mental illness beyond what was called an apathetic temperament, so nothing in the record accounts for him. A well-documented physiological edge case that resists every explanation offered is close to irresistible here.

DetailFour times the standard military ration was not enough to satisfy him.

388 points by marcodiego 16 January 2022 169 comments

Hacker News found it again on 5 Feb 2019.

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In 1978 a proton beam passed through his head; he retired a physicist

Anatoli Bugorski

Posted as “A Russian scientist who was struck by a particle accelerator beam”

Anatoli Petrovich Bugorski, born 25 June 1942, is a retired Russian particle physicist. He is known for surviving a 1978 radiation accident in which a high-energy proton beam from a particle accelerator passed through his head.

He is known for having survived a radiation accident in 1978, when a high-energy proton beam from a particle accelerator passed through his head.

Here is the input nobody wrote a handler for, and the audience reads it the way it reads a crash report: what precisely the beam did on the way through, and how the man went back to work afterwards. The submitted title dropped the name entirely and led with the mechanism, which is the correct way to sell this to this particular crowd. The detail that keeps it in circulation is how ordinary the rest of the biography stayed.

DetailBugorski was born on 25 June 1942; the beam went through his head in 1978.

172 points by thisjepisje 27 July 2014 30 comments

Hacker News found it again on 11 Jan 2011.

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The 1975 book that named the state programmers chase all day

Flow (psychology)

Posted as “Flow”

Flow is the mental state of full immersion in an activity, characterized by energized focus, complete absorption, and a transformed sense of time. The article frames it as a balance between a skill and the difficulty of the task, requiring high concentration. It also distinguishes flow from hyperfocus, which is not always described positively.

Flow is the melting together of action and consciousness; the state of finding a balance between a skill and how challenging that task is.

This is the community that argues about open-plan offices, meeting-free days, and how long it takes to reload a mental stack after an interruption; the article gives that argument a citation and a Hungarian name. The sharpest thing on the page is the hyperfocus caveat, which reframes the same absorption as several unfinished projects and a person who looks unfocused from outside. Programmers know both versions personally and tend to be honest about which one they were in last night.

DetailThe concept was first presented in the 1975 book Beyond Boredom and Anxiety by the Hungarian-American psychologist Mihály Csíkszentmihályi.

98 points by simonreed 19 February 2010 29 comments

Also on the front page that day375 stories posted

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Sixth Edition Unix, rewritten in ANSI C so a class can read it all

Xv6

xv6 is a modern reimplementation of Sixth Edition Unix in ANSI C, targeting multiprocessor x86 and RISC-V systems. MIT built it in 2006 for its Operating System Engineering course.

xv6 is a modern reimplementation of Sixth Edition Unix in ANSI C for multiprocessor x86 and RISC-V systems.

The Lions commentary lineage is about as close as this field gets to scripture, and xv6 is that text made runnable on hardware you actually own. Programmers who spend their careers on kernels they will never read end to end will reliably vote up one they can finish. It took first place for the day over a Julia Computing grant and a fresh libpng CVE, which is a fair summary of the site's priorities.

DetailMIT created it in 2006 for its Operating System Engineering course.

350 points by jdmoreira 14 November 2015 47 comments

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The holiday that lands on the 256th day because a byte says so

Programmer's Day

Posted as “Today is Programmer's Day”

Programmer's Day, also known as the Day of the Programmer and occasionally as Day 2^8, is an international professional day celebrated on the 256th day of each year: September 13 in common years and September 12 in leap years. The number was chosen because 256 is how many distinct values a byte can hold. It is also the highest power of two below 365 and 366.

256 is also the highest power of two that is less than 365 and 366, the number of days in a common year and leap year respectively.

A professional holiday derived rather than decreed is the only kind this audience will accept, and the derivation here is airtight: one byte, and the last power of two that fits inside a year. The date does double duty as an in-joke and a unit test. Posting it on the day itself, in four separate years, is the community keeping its own cron job alive.

DetailIn leap years the observance shifts to September 12 so that it stays on day 256.

Why that dayThe submission was titled "Today is Programmer's Day", and September 13, 2010 was in fact day 256 of that year. The article has come back to the front page on exactly the right day in 2011, 2013 and 2020, sliding to September 12 for the leap year.

Also submitted as Day of the Programmer, Programmer's day, Programmers Day.

240 points by guffshemr 13 September 2010 38 comments

Hacker News found it again on 13 Sep 2011, 13 Sep 2013, 12 Sep 2020.

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Igor Pavlov's LZMA, ported until it felt like it had always been there

XZ Utils

Posted as “Xz”

XZ Utils is a set of free-software command-line lossless data compressors for Unix-like systems, including the lzma and xz programs, with Microsoft Windows support from version 5.0 onward. Compression and decompression use the LZMA algorithm. It began as a Unix port of Igor Pavlov's LZMA-SDK, reworked to fit Unix structure and behavior.

XZ Utils started as a Unix port of Igor Pavlov's LZMA-SDK that has been adapted to fit seamlessly into Unix environments and their usual structure and behavior.

This is infrastructure genealogy, the genre where a file extension you type without thinking turns out to trace back to one person's SDK and a port careful enough to disappear into the platform. Compression ratios are also a permanent standing argument on this site, and any candidate default invites benchmarking against the incumbent.

DetailWindows support arrived only with version 5.0; before that it was Unix-like systems only.

In 2010 /wiki/Xz redirected to the compression tool; it is a disambiguation page now.

Also submitted as Xz.

232 points by golwengaud 24 June 2010 64 comments

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The one command that can produce almost any connection you need

Netcat

Posted as “I never realized how useful netcat is”

Netcat, usually invoked as nc, reads from and writes to network connections over TCP or UDP. Wikipedia frames it as a dependable back end, meant to be used directly at a prompt or driven by other programs and scripts. Port scanning, file transfer and port listening all come out of the same small binary.

The command is designed to be a dependable back-end that can be used directly or easily driven by other programs and scripts.

The submitted title was a confession rather than a claim, which is the exact shape of this site's affection for a Unix primitive: a tool people already have in their fingers and still keep finding new uses for, because it does one composable thing and then gets out of the way. A utility described as able to produce almost any kind of connection its user could need is also, obligingly, a reconnaissance tool, and the audience reading it in 2009 understood both halves. Write-ups of the things already in your muscle memory reliably outrank the day's product news here.

DetailIt speaks both TCP and UDP, and does port scanning, file transferring and port listening from the one command.

190 points by tzury 16 September 2009 32 comments

Hacker News found it again on 5 Nov 2010.

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S-expressions compiled straight down to Python's syntax tree

Hy (programming language)

Posted as “Hy”

A Lisp dialect built to interoperate with Python, Hy works by translating s-expressions into Python's abstract syntax tree. Paul Tagliamonte introduced it at PyCon 2013. Because Lisp allows code to be operated on as data, Hy can be used to write domain-specific languages.

Hy is a dialect of the Lisp programming language designed to interact with Python by translating s-expressions into Python's abstract syntax tree (AST).

Two constituencies meet cleanly here: people who miss macros and people who cannot leave Python's libraries, and Hy's claim is that targeting the AST rather than emitting source text gets you both. That single implementation decision is the whole argument, and it is precisely the kind of detail this readership will read a short encyclopedia entry to confirm. A submission titled 'Hy' pulled 850 points, which means the audience got the trick from the first sentence.

DetailHy was introduced at PyCon 2013 by Paul Tagliamonte.

In August 2019 /wiki/Hy still pointed straight at the Lisp dialect; it is a disambiguation page now.

850 points by tosh 4 August 2019 141 comments

Hacker News found it again on 7 Nov 2016.

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The rc in .bashrc is a script processor from 1960s CTSS

RUNCOM

Posted as “Run Commands, the 'rc' in '.bashrc'”

Wikipedia's summary of RUNCOM is one sentence long: RUNCOM is a CTSS macro command, or script, processor. That single line is the whole of it, with no dates, no author, and no history. Whatever made this worth posting sits in the submitted title rather than on the page; the title is what supplies the expansion, run commands, the rc in .bashrc.

RUNCOM is a CTSS macro command (script) processor.

Programmers type those two letters most days of their working lives, in .bashrc, .vimrc, .zshrc, .npmrc, and almost none of them have asked what they abbreviate. The answer is a macro processor for CTSS, a 1960s time-sharing system that almost nobody reading had ever touched, still fossilised in the filenames on their laptops. That is software archaeology at its purest, the etymology of a convention nobody alive chose and nobody can now remove, and it was worth 620 points for one sentence of encyclopedia.

DetailWikipedia's entire summary of RUNCOM is one sentence: a CTSS macro command (script) processor.

Also submitted as Run commands.

620 points by rspivak 1 September 2019 126 comments

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Enlarging pixel art needs filters that refuse to be faithful

Pixel art scaling algorithms

The article covers graphical filters built specifically to enlarge hand-drawn 2D pixel art. Wikipedia classifies them as a form of automatic image enhancement rather than plain resizing. Their methods differ significantly from ordinary image rescaling, whose goal is to preserve the appearance of the original.

Pixel art scaling algorithms employ methods significantly different than the common methods of image rescaling, which have the goal of preserving the appearance of images.

Anyone who has written an emulator front end or shipped a sprite sheet has run straight into this: smooth interpolation turns pixel art to mush, nearest neighbour turns it to bricks, and neither is what the artist drew. What the page collects is the pile of hand-tuned heuristics people invented instead, each one a named algorithm with its own characteristic failure mode. That combination, small problem, many rival solutions, all inspectable, is close to the platonic Hacker News page.

DetailWikipedia files these filters as automatic image enhancement, a different goal from ordinary rescaling.

208 points by gregschlom 23 December 2010 32 comments

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Bird-oid objects: the 1986 algorithm behind simulated flocking

Boids

Boids is an artificial life algorithm developed by Craig Reynolds in 1986 and published at SIGGRAPH in 1987, simulating the flocking of birds and related group motion. The name shortens "bird-oid object" while nodding at the New York pronunciation of "bird". Ichiro Aoki's closely related work appeared in 1982, five years earlier.

The name "boid" corresponds to a shortened version of "bird-oid object", which refers to a bird-like object

Boids is the canonical demonstration that behavior can be much larger than the code producing it, and it is short enough that most readers have implemented some version of it on a slow afternoon. It also satisfies the ancestor instinct: a named person, a datable paper, a technique still running underneath things people ship. And the extract hands the comment section its argument on a plate, since Aoki got there first and the algorithm carries Reynolds' framing anyway.

DetailIchiro Aoki published closely related work in 1982, five years before Reynolds' boids paper.

391 points by jonbaer 28 March 2020 80 comments

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Perl verse, posted anonymously in 1990, that also runs

Black Perl

Black Perl is a code poem written in the Perl programming language and posted anonymously to Usenet on 1 April 1990. It is written in Perl 3, and the poem can be executed as a program. Perl programmers have kept it in circulation ever since as a piece of Perl poetry.

Written in Perl 3, the poem is able to be executed as a program.

Perl's grammar is loose enough that English sentences sometimes parse, and Black Perl is the artifact you hold up to prove it: not a joke about a language but a joke made out of one. A community that argues constantly about expressiveness has a weakness for things that are literature and a valid parse tree at the same time. The anonymity helps too; there is no author to credit, only a Usenet post that outlasted everything around it.

DetailIt was posted anonymously to Usenet on April 1, 1990, written in Perl 3.

124 points by soundsop 30 January 2010 40 comments

Hacker News found it again on 12 Sep 2013.

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Hopper wanted code written in English, then developed COBOL

Grace Hopper

Grace Brewster Hopper (1906 to 1992) was an American computer scientist, mathematician and United States Navy rear admiral. She was the first to devise the theory of machine-independent programming languages and used it to develop FLOW-MATIC and COBOL, and she was one of the first programmers on the Harvard Mark I. She held a Yale PhD, taught mathematics at Vassar, joined the Navy Reserve during the war, and later worked on UNIVAC I at Eckert-Mauchly, where she managed development of one of the first COBOL compilers.

She is credited with writing the first computer manual, "A Manual of Operation for the Automatic Sequence Controlled Calculator."

Hopper is one of the small set of people this site treats as direct ancestors, and her central conviction, that programming should be simplified with an English-based language, is the origin of every abstraction argument still running in the comments. The entry also holds an unusually literal set of firsts: the first theory of machine-independent languages, the first computer manual, and one of the first COBOL compilers. Posting the encyclopedia page is how the community does lineage.

DetailBy 1952 she had finished her program linker, originally called a compiler, written for the A-0 System.

190 points by networked 31 August 2013 54 comments

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When 64K was a vast amount and the entire address space

Minimalism (computing)

Minimalism in computing is the application of minimalist philosophies and principles in the design and use of hardware and software, meaning systems designed to use the least hardware and software resources possible. The article anchors it in the late 1970s and early 1980s, when programmers worked within relatively expensive and limited resources: eight or sixteen kilobytes of RAM was common, 64 kilobytes was considered a vast amount and was the entire address space accessible to the 8-bit CPUs of the earliest personal computers, the most common storage medium was a 5.25 inch floppy disk holding 88 to 170 kilobytes, and hard drives of five to ten megabytes cost thousands of dollars. Memory capacities then expanded by orders of magnitude while the system requirements of legacy software stayed exactly where they were, so the most elaborate programs of that era now read as minimalist.

the GNU Emacs text editor, which gained the backronym "Eight Megabytes And Constantly Swapping"

Frugality as a moral position is one of this site's oldest reflexes, and the value of the page is that it supplies the numbers that turn the position into an argument instead of nostalgia. The Emacs backronym is a shibboleth: a joke that every reader knows and that stops being funny at the moment their own binary starts swapping. Worth noting the scale of the room in July 2008, when the entire site posted 95 stories in a day and fifth place cost 29 points, so this is a handful of people agreeing quietly rather than a stampede.

DetailThe most common storage medium of the period was the 5.25 inch floppy disk, holding from 88 to 170 kilobytes.

29 points by zen53 19 July 2008 18 comments

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